This invention generally relates to injectors and fuel nozzles for high temperature applications, and more particularly, to fuel injectors and nozzles for gas turbine engines.
In gas turbine engines, fuel injectors are typically used to inject fuel in a spray or atomized form into a combustion chamber of the engine. The atomized air/fuel mixture is then combusted to create the energy required to sustain engine operations. Prefilming air-blast fuel injector nozzles for issuing atomized fuel into the combustor of a gas turbine engine are well known in the art. In this type of nozzle, fuel is spread out into a thin continuous sheet and then subjected to the atomizing action of high-speed air. More particularly, atomizing air flows through concentric air swirl passages that generate two separate swirling airflows at the nozzle exit. At the same time, fuel flows through a plurality of circumferentially disposed ports which are oriented in an axial, radial, tangential or a combination of these directions and then onto a prefilming surface where it spreads out into a thin sheet before exiting the edge of the prefilming surface and interacting with the adjacent air streams.
Conventional fuel nozzles generally include a plurality of small slots or openings through which fuel flows. As a result of the small size of these openings, such nozzles are difficult to manufacture and therefore costly. In addition, these small openings are prone to blockages or plugging as a result of coking of the fuel passing there through.